1. Field of the Invention
This invention pertains to the field of polyurethane plastics.
2. Description of the Prior Art
The use of a polyol in the preparation of polyurethanes by reaction of the polyol with a polyisocyanate in the presence of a catalyst and perhaps other ingredients is well known. Conventional polyols for flexible polyurethane foams are usually made by the reaction of a polyhydric alcohol with an alkylene oxide, usually ethylene oxide and/or propylene oxide, to a molecular weight of about 2000 to 3000 and above. These polyols are then reacted with polyisocyanate in the presence of water or other blowing agents such as fluorocarbons to obtain polyurethane foams. The prior art describes modified polyols in which vinyl monomers such as styrene or acrylonitrile or other materials such as hydrazine hydrate have been included to improve the properties of the polyol and thus, the properties of the resulting foam. However, some of these prior art materials are highly toxic and require in addition, stripping of unreacted vinyl monomers or water of hydration. U.S. Pat. No. 4,107,102 describes the manufacture of polyurethane foam using a polyol containing hydrazine and its adducts.
German Offenlegungsschrift No. 2,110,055 discloses a process for making a polyurethane product whereby a hydroxyl-containing amine is included in the formulation in a one-shot process. That is, the hydroxyl-containing amine is simply included initially with the polyol and the polyisocyanate and a polyurethane product results. The German process does not use a polyurea polymer polyol which is then reacted with a polyisocyanate. My invention makes improved polyurethane foams over the process of the German patent as will be made clear by the disclosure and the examples which follow.
U.S. Pat. No. 3,325,421 discloses the method of making a stable dispersion of a urea in a composition comprising an organic polyisocyanate, a diamine and a compound having at least two alcoholic hydroxyl groups.